The present invention relates generally to automatic dishwashers and the like, and more particularly, to fluid sealing arrangements for dishwasher doors.
Automatic dishwashers have generally included an internal chamber or enclosure for retaining dishes and other articles to be washed. Cleaning fluid, such as a soap or detergent and water solution or water alone, is sprayed at the dishes and typically spatters throughout the enclosure Prior to being collected in a tub portion at the bottom of the enclosure. Cleaning fluid and any debris removed from the dishes can accumulate within the tub prior to being filtered, recirculated, and/or drained by the dishwasher pump. The door to such enclosures is usually pivotable from an open, horizontal position to a closed, vertical Position. When the door is in the closed position a resilient sealing gasket is usually disposed between the door and the enclosure opening along the top and sides of the door to prevent leakage out of the enclosure during operation.
Previous dishwashers have also employed such gaskets along the bottom of the door, although the stresses on the gaskets at those locations during opening and closing of the door may be significantly different from the gasket stresses along the sides and top of the door. In certain circumstances specially formed and/or more expensive gaskets were required in order to avoid premature wear and leakage during operation. Accordingly, previous dishwashers have also employed a lower extension of the door into the tub below the level of spraying to prevent leakage caused by spraying of the cleaning fluid. This extension may, for example, penetrate down to or below the level of accumulated fluid in the tub. Unlike the sealing gaskets, these extensions need not require compression between the door and the enclosure opening or tub in order to create an adequate seal. Sealing against spray is, in effect, accomplished in these arrangements by the tortuous or blocked path formed to the enclosure opening. Accordingly, such sealing arrangements can be more cost effective and have an increased useful life.
However, in some of those dishwashers where fluid does accumulate in significant amounts in the tub, it may be possible for surges in the accumulated fluid to cause leakage past the downward extension of the door. Even where this accumulation is below the level of spraying, surges can cause the accumulated fluid to move outward to and up the sides of the tub through an opening or gap between the tub and the downward extension of the door. As a result, spattering fluid can escape the enclosure and be deposited outside the dishwasher or on other dishwasher components.
Surges can be caused by several types of events. For example, if the dishwasher door is opened during operation the dishwasher will usually discontinue spraying, but relatively cold air is introduced to the enclosure. When the dishwasher resumes operation this cold air can be heated very quickly and tend to expand in volume. Such expansion can create a short term pressure increase within the enclosure and cause sudden movement of fluid in the tub.
Another potential source of minor leakage is termed "corner spit" or "corner congregation". During operation of dishwashers using rotating spray jets, fluid can tend to congregate in the corners of the enclosure. That fluid has a tendency to splash upwardly after falling from the enclosure sides into the tub. Where this splashing occurs at the corners of the door, fluid can also spatter behind the lower extension of the door and escape the enclosure. To the extent such leakage does occur it has been observed to be particularly prominent at the left side of the door.
At the same time, however, whatever device is employed to prevent surge or corner spit leakage must avoid depositing run-off fluid outside of the dishwasher when the door is opened in order to function most effectively. Run-off fluid from the top and sides of the door tend to remain on the enclosure side of the door and, thus, are deposited back in the tub by sliding along the lower extension of the door when the door is opened. Surge and corner spit leakage, on the other hand, are behind the inner wall of the door and, thus, cannot slide back into the tub so readily.
Accordingly, it is an object of the present invention to provide an improved sealing arrangement for automatic dishwashers.
Another object of the present invention is the provision of a cost effective, reliable seal arrangement for dishwasher doors.
A further object of the present invention is to provide a device for preventing surge spatter and corner spit leakage from penetrating a tortuous path-type fluid seal at the lower portion of a pivotable enclosure door.